1. Field of the Invention
The present invention relates to the field of bicycle, and in particular to a twin clutch hub, which features both great output of torque power provided by a ratchet wheel and gap-free non-loading transmission provided by a one-way roller clutch.
2. The Related Arts
To cope with high fuel price era and to suit the need of environment conservation and reduction of air pollution, using bicycle is now increasing. Further, large cities around the world are all ambitious in developing an easy-borrow-easy-return project for bicycles, which allows a user to borrow a bicycle at one site and to return the bicycle at another site in order to cut down the use of automobiles and motorcycles. Apparently, bicycle popularization is now upgraded to national level. In addition, besides being a transportation measure, the bicycle is also a measure of exercise, for pedaling a bicycle is actual a kind of exercise.
Some of the currently available bicycles are provided with a ratchet pawl based clutch and the ratchet pawl based clutch has a significant returning side tooth backlash. This lowers down the operation efficiency and also causes uncomfortable feeing. Further, such a significant returning side tooth backlash is of even greater influence on the vertical treading type bicycle pedals. Apparently, further improvement is desired.
Furthermore, the bicycles that are currently available in the market do not use one-way roller clutches, simply because the one-way roller clutches can only stand for reduced torque powers. Consequently, the one-way roller clutch is of no use in situations where a great torque power is needed, such as uphill riding.